commit d53ba47484ed6245e640ee4bfe9d21e9bfc15765
(Btrfs: use commit root when loading free space cache) has remove
the deadlock check, and the related comments can be removed as well.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <jbacik@fusionio.com>